An optical information reading device is well known that optically reads an information symbol, such as a QR code (please refer to FIG. 1A), a barcode (please refer to FIG. 1B), and the like, attached on a product and a document.
The optical information reading device is configured of a small body case including a reading window provided in its one end, a light detector such as a Charge-Coupled Device (CCD) sensor, an imaging unit including an imaging lens, and a lighting device such as a Light Emitting Diode (LED), and the light detector, the imaging unit, and the lighting device are installed in the body case.
When a user desires to read an optical symbol attached on a product using the configuration of the optical information reading device, the user may, for example, enable the reading window to face the product and may dispose the optical information reading device at a predetermined distance away from the product.
The optical information reading device is disposed in this state, and the lighting device applies illumination to the information symbol through the reading window and emits the illumination to the information symbol. A light reflected from the information symbol by the emitted illumination may be incident to the imaging unit through the reading window. The light incident to the imaging unit is in focus by the imaging lens and an image is formed in the light detector. Accordingly, an image corresponding to the information symbol is read by the light detector. Information stored in the information symbol may be decoded based on a light and shade pattern between bright (white) pixels and dark (black) pixels in the read image.
When the optical information reading device is used to read an information symbol printed on a predetermined paper, illumination emitted to the information symbol maybe minor-reflected based on an incident angle of the illumination with respect to the paper, and at least a portion of the information symbol may be recognized to be a bright pixel (white pixel) by the mirror reflection, irrespective of black information stored in the corresponding portion. Therefore, the optical information reading device may cause a problem in that information stored in an information symbol is wrongly read. Also, when a symbol that is directly marked on a metal surface of a product through direct marking is read, the mirror reflection may frequently occur and thus, information stored in an information symbol may not be accurately read.
Also, an amount of information that the information symbol may store is limited and thus, the information symbol generally links address information of a place where large capacity information is stored. Therefore, it is inappropriate that the large capacity information is directly transmitted using the information symbol.
Also, the information symbol stores only information formed during a process that produces the symbol, and has a drawback in that additional information is not added to the formed information symbol or the information symbol is not corrected.